Is it harmful to the buffer spring to keep an AR stored with the bolt locked back. I know that springs are supposed to wear out only through repeated compression and release. I keep all mags loaded, but for some reason I don't feel as comfortable leaving my rifle with the bolt back, safety on and a loaded mag inserted. Strictly from a mechanical, rather than safety standpoint. I'm not sure I'll keep it that way anyway, but I'd like to know the pros and cons.